Surgical instruments and other medical devices used for clinical or laboratory purposes must be reprocessed or decontaminated after use, if they are non-disposable, in order to prevent infection and cross contamination. The decontamination process typically involves 3 steps; a washing/cleaning step to remove blood, proteins and other bodily contaminants from the instruments and/or devices, followed by a disinfection step to allow safe handling and inspection of the devices/instruments prior to packaging, and the final step of sterilisation. If the devices/instruments are sterilised without effective washing/cleaning or disinfection, sterilisation is likely to be ineffective.
The cleaning/washing and disinfection steps are two distinct stages in the decontamination process but are often undertaken in the same washing apparatus (a washer disinfector) in a sequential manner using different programmable cycles. The efficacy of the disinfection step (a heat process) can be verified thermometrically but the efficacy of the washing/cleaning step cannot be easily measured parametrically. As such, a test substance known as a “test soil” is used as a challenge in the washing apparatus and includes a pre-determined level of contaminants thereon, which is designed to simulate typical soiling of surgical instruments and medical devices during normal use. The “test soil” is coated onto a selection of surgical instruments and/or medical devices and is allowed to dry onto to the same for a period of time. The instruments and/or devices are then processed through the washing apparatus or washer disinfector to test the efficacy of the washing/cleaning step. Removal of “test soil” from the instruments and devices can be determined visually since most test soils contain blood or dyes to make them visible. Alternatively, a chemical detection method such as ninhydrin (1,2,3-indantrione monohydrate) can be used. The ninhydrin method utilises the reaction of amino acids, peptides and proteins with the ninhydrin to produce a highly coloured compound. A selection of instruments are swabbed with water, then the swab is treated with ninhydrin. If protein is present on the instruments, i.e. if the instruments are not clean, the swab turns a purple colour.
Conventional test soils typically include animal blood or blood fractions and other animal products, such as egg or egg fractions. However, the natural variability of the test soil components can mean that the test soils may not perform consistently from batch to batch. In addition, the test soils need to be coated onto a range of instruments and allowed to dry for between 30 minutes to two hours prior to washing. This is time consuming and is typically a major inconvenience for busy hospital departments. There are also problems associated with the availability of fresh test soil components and, due to the problems mentioned above, the test is normally conducted on a periodic basis which, in some cases, is as infrequently as four times a year. As such, any problems which might arise with the washing process are only identified infrequently. Furthermore, due to the well known risks associated with using blood products, it is undesirable to use the same in the manner described above.
An example of a conventional test soil device which is used in the monitoring of the cleaning efficiency of washer disinfection apparatus includes a standardised test soil substance which is placed at an amount of 20 mg on a small stainless steel plate. The test soil consists of 95% water soluble components and 5% water insoluble fibrin fibres which correlates to coagulated human blood.
A problem associated with such a conventional test device is that it is generally uni-directional and is exposed to washing and cleaning in one direction only. However, since the efficacy of the washing and cleaning processes is dependent on factors such as the operating cycle being used, temperature and pressure of the water, the location of the test device in the washing apparatus, loading of the washing apparatus and whether the test device is adjacent water/fluid jets in the washing apparatus, if only a single surface of the test device has a test soil substance provided thereon, it is unlikely to provide an accurate representation of the efficacy of washing and cleaning of the washing apparatus.
It is therefore an aim of the present invention to provide washing test apparatus which removes the requirement for coating instruments with a test soil substance.
It is a further aim of the present invention to provide washing test apparatus which is quick and easy to use, thereby ensuring regular use of the apparatus.
It is a yet further aim of the present invention to provide washing test apparatus which provides a more accurate and multidirectional challenge that is representative of cleaning/washing efficacy in washing apparatus.
It is an aim of the present invention to provide holder means for use with a test soil device.
It is a further aim of the present invention to provide a test soil device for use with holder means.